Complete analysis of the composition and biosynthesis mechanism of specific O-polysaccharides present in a periodontal pathogen's LPS

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K11451
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Morphological basic dentistry
• Research Institution: Nagasaki University
• Principal Investigator: SHOJI Mikio 長崎大学, 医歯薬学総合研究科(歯学系), 助教 (10336175)
• Co-Investigator(Kenkyū-buntansha): 橋本 雅仁 鹿児島大学, 理工学域工学系, 教授 (30333537)
• Research Collaborator: NAKAYAMA Koji ; YUKITAKE Hideharu
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 歯周病関連細菌 / リポ多糖

Outline of Final Research Achievements

Porphyromonas gingivalis is known as a keystone pathogen of chronic periodontitis. This bacterium secretes many virulence proteins via the type 9 secretion mechanism (T9SS). Some of the T9SS cargo proteins are covalently bound to A-LPS and are anchored on the cell surface. This bacterium has two kinds of LPSs, A-LPS and O-LPS, however, their biosynthesis mechanism is unknown. In this study, we analyzed the biosynthesis mechanism of O polysaccharide of both LPSs.
About 14 glycosyltransferases that have not been characterized from genomic information, we tried to create their gene mutants. From the mutant study analysis, some genes involved in O-polysaccharide biosynthesis in A-LPS and O-LPS were identified, and the order of their biosynthesis was clarified.

Free Research Field

口腔病原微生物学分野

Academic Significance and Societal Importance of the Research Achievements

我々は、歯周病細菌Porphyromonas gingivalisの病原性プロテアーゼなどの分泌タンパク質が新規の分泌装置である9型分泌機構によって菌体表面に輸送されること、さらに、菌体表面に出たこれらのタンパク質は本菌特異的な病原性LPSのO多糖鎖に結合することで局在化すること、を見出していた。この病原性LPSのO多糖鎖については我々の知見と相反する報告があり、問題となっていた。本研究はその問題に取り組み、O多糖鎖の生合成機構を新規に提唱した。本研究成果は、将来の応用研究に展開させるうえで重要な基盤となる。